Average THC Content in Seized Cannabis Samples (1972 - 2008)

When assessing claims about THC levels in marijuana, it is important to have not only the measures of average THC content, but also the number of samples of each type that were used to derive the measurements. Without knowing the number of samples, it is simply not possible to determine if the reported THC levels are truly representative of the levels in what is being consumed by cannabis users. Likewise, comparing across sample types is illustrative only to the extent that the number of samples is known. The importance of this is readily seen in the chart below left with the data for hash oil. In 2004, the potency of hash oil appears to have skyrocketed to an average of over 30 percent THC. But that is the average of only four samples. As usual, when it comes to the war on drugs, what we aren't being told is much more important and useful than what we are being told.

Although all of the available data on average THC content is depicted below, only the data for marijuana and (to a lesser extent) sinsemilla are based on a sufficient number of samples to provide meaningful comparisons. The raw data is confounded not only by the overall number of samples tested, but also by how the samples were treated from the time they were seized to the time they were measured. THC readily degrades in the presence of heat and light, so many of the early years of sample data (even those with enough samples to be be useful) are essentially worthless as there were no quality control procedures in place to govern the handling and storage of the samples. Later data has much greater fidelity as there are, in general, both a larger number of samples for a given sample type, and the samples themselves are more likely to have been handled with standardized procedures.

Ultimately, what we need to know and still have no data for, are the highest recorded values for each type of cannabis product for each year. Everyone who was smoking cannabis back in the 1970's, and still does so today, will tell you flat out that there was higher quality marijuana available then too. The big difference today is simply that there is wider availability of higher quality product. Stronger cannabis products aren't "more dangerous" -- they're just stronger, which means less product is required to get the same effect. It's quite similar to the range of alcohol products between beer and whiskey. Whiskey may be "10 times stronger" than beer, but the drug in question (alcohol) is still the same thing.

Hashish is composed mainly of the resin of the cannabis plant, mixed with some plant particles and shaped into a variety of forms such as balls, sticks or slabs which are very hard, dark green or brownish colored.